This binding ruler is designed for 2 1/2 inch strips. A groove located on the underside of the ruler, locks the binding in place and will allow you to precisely attach a binding while it is on the long arm with a perfect quarter inch seam. You will not even need pins! You will be able to create accurate diagonal stitch offs in the corners to create a beautiful miter and continue down the sides of your quilt. If you are a hobby longarmer, or in it for a business, this will make adding your bindings a breeze.